Serene isn’t just a distraction blocker: it’s a productivity system built around periods of deep focus. Users choose a list of websites and apps they find distracting, then block them when it’s time to buckle down and get some work done. But there’s more than that here.

The app is built around planning your day. List how many things you want to work on and how long they’ll take. Then, when it’s time to work, click the Go Serene button to start a timer. All of your distractions will be blocked, optional concentration music will play, and you’ll be reminded that it’s time to focus and shown your countdown timer every time you try to open a site that you shouldn’t. These elements work really well together—you’re not only blocking distractions; you’re also reminding yourself of what you’d like to accomplish.

You can streamline your focus sessions even more with Serene’s Zapier integrations, which can create focus sessions from apps like Trello, Asana, Todoist, and any other task management app you can think of.

Serene pricing: $4/month. Free trial limited to 10 free deep work hours.

Best focus app for scheduled system-wide blocking

Cold Turkey Blocker (Windows, macOS)

Cold Turkey Blocker is, in a word, customizable. Install this site-blocking app, and you can create lists of websites and desktop apps to block, then set a schedule for blocking. You could, for example, block social media and video sites during every work day. You could also block work apps, like Slack, when the work day ends. It’s all up to you. Or, if you prefer, you can turn blocking on and off manually. There’s even a mode called Frozen Turkey, which prevents you from accessing your computer entirely: turn it on, and you’ll see a blank screen until your scheduled outage is over.

Because this is a system-wide tool and not just a browser extension, you can’t work around it by changing browsers. But it goes further than that—there are all kinds of settings that thwart future versions of yourself from working around your current intentions.

You can block the Time & Language settings, stopping you from working around a scheduled block by changing your computer’s time. You can stop yourself from accessing the Chromium Task Manager, which you could, in theory, use to disable the blocking extension. You can even make it impossible to uninstall Cold Turkey Blocker until your scheduled blocking is complete. I could go on, but the basic point is that you can stop yourself from working around your block. Try this out if you’re the self-sabotaging sort.

Cold Turkey pricing: $39 Pro plan with unlimited blocking, scheduling, and the ability to block desktop apps as well as websites.

Best free browser-based website blocker

LeechBlock NG (Chrome, Firefox, Edge, Opera)

LeechBlock NG (the NG stands for “next generation”) works on most major browsers, is free, and gives you a bunch of options for blocking distractions. You can make lists of sites to block, then restrict them in all kinds of ways.

You can schedule times for apps to be blocked outright, which is very straightforward. Alternatively, you can limit your time on distracting apps by setting up rules. For example: you could give yourself 20 minutes of YouTube time every day, or four minutes of Twitter every hour. You can get even more specific, if you want, combining time limits with a schedule—think five minutes of Instagram every hour between 8 a.m. and 5 p.m. Or, if you don’t want to mess with schedules, you can trigger a one-off “lockdown” schedule.

It’s a lot of power, particularly for a free tool, and you can even lock down the settings during block sessions if you want. The only downside: this is a browser extension, not an app, so you can work around it by switching browsers. If you can avoid that temptation, though, LeechBlock should work nicely.

LeechBlock pricing: Free

Best focus app for time tracking with built-in website blocking

RescueTime (Windows, macOS, Android)

RescueTime isn’t, primarily, a distraction blocker—it’s one of the best time tracking apps. But it does include a distraction blocking feature called FocusTime, which allows you to block distractions using your time tracking history.

This works using data you’re already providing RescueTime, which allows you to designate apps and websites as productive, distracting, or very distracting. In FocusTime, you can choose to block distracting apps or even just anything you haven’t specifically tagged as productive. It’s a great way to block distractions without having to build a separate block list, particularly if you’re looking for a time tracking app anyway.

You can block distractions automatically using RescueTime’s Zapier integrations, which allow you to do things like schedule a daily FocusTime session.

RescueTime pricing: $12/month. Note that the free version of RescueTime does not include distraction blocking.

Best focus app for motivating you to put down your phone

Forest (Android, iOS, Chrome)

Your phone is a time machine, but not in a useful way. It’s way too easy to pick it up and then notice a couple of hours have disappeared. Forest is an adorable app designed to help you with that.

The idea is simple: you open the app and say you want to plant a tree. Then you put your phone down. If you pick up your phone and switch to another app, your tree will die. Last 25 minutes, and your tree will live. Over time, you’ll grow an entire forest of trees, a reminder of all the time you intentionally spent getting things done instead of scrolling through Twitter. Plus, if you use a paid version of the app, your focus time could help fund real trees via a partnership with Trees for the Future.

Forest also offers a Chrome extension, meaning you can grow trees on your computer as well. This one works more like the other apps in this list but with an option to load distracting sites if you want to. The downside to overriding the block: you’ll have to deal with delightfully twisted copy. “This will kill your cute, little tree,” you’re warned. It gets worse: try to look at a distracting site and you’re told, “your tree is dead.” It’s manipulative, sure, but it’s manipulating you to spend your time wisely. Better than the reasons most apps manipulate you.

Forest pricing: Free on Chrome and Android, $1.99 for iPhone. Android Pro version costs $1.99, one-time, and offers syncing across devices and more tree varieties.

Best focus app for a nuclear option for Mac users

SelfControl (Mac)

SelfControl looks spartan: there’s a blocklist, a dial for setting how long your block period should be, and a start button. That’s it. But it stands out for one key reason: it’s impossible to undo.

Seriously, this app is hardcore. Closing the app does nothing—all of your distractions are still blocked. Deleting the app doesn’t do anything, and neither does rebooting your computer. The only way to disable blocking, once you set the timer, is to reinstall macOS entirely (which would delete all of your apps, settings, and documents).

It is truly the nuclear option for blocking distractions—none of the other apps on this list come close to this level of permanence. If you’re the sort of person who starts blocking, then caves, this app is for you.

SelfControl pricing: Free